1. Field of the Invention
This invention relates to temples of an eyeglass frame, the temples being foldably coupled to the eyeglass frame via joints and being allowed to be further slightly opened outward from the state opened due to the joints owing to action of magnetic force.
2. Prior Art
A joint that works to slightly push open a temple of an eyeglass frame in a state where it is opened is called a spring hinge, and is much used as means for coupling the temples to the eyeglass frame. For example, a “coupling structure” according to JP-A-2001-290108 is designed to couple the temples of the eyeglass frame to the endpieces in a manner to rotate relatively, wherein an end of the temple is branched into a fork to form a pair of piece members maintaining a gap in the horizontal direction, the piece members are pierced, extending grooves opposing each other are formed in the piece members along the lengthwise direction of the temple, an urging member is held between the opposing grooves, and a moving member is attached to the urging member so as to be urged to the endpiece by the urging force of the urging member and to move in the gap of the temple.
The temple in the opened state is constituted to be pushed open outward by the urging force of the spring in the return direction. For this purpose, a coil spring is used. That is, the spring force is produced by compressively deforming the coil spring, and as a result, it requires a slide member for compressively deforming the coil spring. However, infiltration of dust and occurrence of rust hinder the slide motion of the slide member and the temple often fails to be smoothly opened. Moreover, the hinge incorporating a coil spring is complex in the structure, and accordingly it is fabricated through an increased number of steps and becomes expensive. Further, the complex structure is liable to become broken down. Once broken down, it must be repaired but the repair is difficult due to the complex. Moreover, the spring hinge can be applied to metallic temples but cannot be applied to plastic temples.
In order to solve the above problems, there has been known an eyeglass frame incorporating magnets to exhibit the same function as that of the spring hinge (see U.S. Pat. No. 5,682,222 entitled “SPECTACLE FRAME HAVING MAGNETIC COUPLING”). According to the above invention, one end side of the temple rotatably coupled to the endpiece via a joint is extended from the joint portion on the outer side surface of the endpiece in parallel in the direction of rim, and the end of the temple and the endpiece are attracted by each other by using magnets. Since the end of the temple is overlapped on the endpiece, the end of the endpiece has a pivot shaft at a protruded portion that protrudes outward. Further, an elongated hole is formed in the corresponding portion of the temple to which the pivot shaft fits, and the temple that is opened can be further pushed open outward. In the above eyeglass frame, if the temple is pushed open outward, a triangular gap forms between the endpiece and the end of the temple. Here, however, the opposing magnets attract each other so as to eliminate the gap between the endpiece and the end of the temple, i.e., so as to pull the temple that is pushed open back to its initial position.
In the above eyeglass frame having magnetic coupling, however, since one end side of the temple is overlapped on the outer side surface of the endpiece, the two side portions of the rims become thick and swell sideways. Therefore, limitation is imposed from the standpoint of aesthetic appearance. Besides, in a state where the temples are folded, the ends of the temples on the joint side protrudes toward the outer side of the joints, resulting in an increase in the width correspondingly and requiring an increased space for accommodation arousing such a problem that an eyeglass casing of an increased size is necessary.